Web pages can provide user interfaces which permit users to access and manipulate information both on the World Wide Web (“WWW”) and on intranets maintained for internal use by various organizations. A web page is a document which is associated with a Uniform Resource Locator (“URL”) or other suitable address and which is viewable by a browser. In this specification the term “web page” has a broad meaning and is not limited to documents available on the world wide web of the Internet. Currently available browsers include Navigator® from Netscape Communications, Inc. and the Internet Explorer® from Microsoft Corporation. A web page includes information and instructions provided in a suitable mark up language such as Hypertext Markup Language (“HTML”) or Extensible Markup Language (“XML”) which inform browser software how the information is to be formatted and displayed to a user.
Web pages do not merely provide static information but can also contain dynamic content. For example, web pages can serve as interfaces to various applications including applications which permit searching for, formatting and displaying information from databases. Existing computer software facilitates the creation of interactive web pages. For example, web publishing software such as WEBSPHERE STUDIO™ from IBM Corporation or VISUAL INTERDEV™ from Microsoft Corporation both provide visual development environments within which web page authors can design web pages using pre-built components. This speeds the development process. Component technology enables e-business and other web-based applications to be created and integrated by using pre-built, pre-tested and reusable components. This is faster and lower in cost than is building web sites from scratch.
One environment in which reusable components can be combined and customized to create web sites is the JAVA™ environment. A Java Server Page (“JSP”) may contain text as well as various objects capable of generating dynamic content. The objects may include code in the form of JavaBeans™, JDBCTM objects, Enterprise Java Beans™ and Remote Method Invocation, for example.
Other environments use Design-time Controls (“DTCs”) as reusable components. A DTC is an ActiveX control that implements a special interface for generating text. A DTC may be used at design time to insert significant amounts of HTML text into a web page. The specific text which is inserted can be determined by a set of properties selected by the web author at design time. The generated text (which may be called “run-time” text because it is used when the web page is displayed by a browser) is saved together with text for other components of the web page in a file. The file can then be placed on line to be accessed by users. A DTC is not active at run-time.
While current web publishing software greatly facilitates the initial creation of complex web pages, it remains time consuming to update web pages. One reason for this is that the characteristics of a previously designed web page are defined, in part, by the properties of replaceable components such as DTCs. Where an original DTC is replaced with a new or upgraded DTC, any properties which may have been set for the original DTC are lost. Thus a web page author updating a web page may need to labouriously locate each DTC which has been changed and specify all of its properties.
There is a need for a system capable of upgrading and updating web pages which avoids the need to re-specify all of the properties for a component if the component is updated. There is a particular need for such a system which is capable of working with current and future web publishing systems.